package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	file, e := os.Create("01.txt")
	if e != nil {
		fmt.Println("error.", e)
		return
	}
	defer file.Close()

	writer := bufio.NewWriter(file)
	for i := 0; i < 100; i++ {
		writer.WriteString(fmt.Sprintf("hello_%d\n", i))
	}
	writer.Flush()

}
